1. Field of the Invention
The invention relates to a new paradigm of disease centering around the metabolic pathways of S-adenosyl-L-methionine (SAM), the intermediates of these pathways and other metabolic pathways influenced by the SAM pathways. Specifically, the invention relates to analyzing and regulating SAM pathways that exist in association with a disease or condition including cancer and a number of diseases or conditions connected with degeneration and aging. More specifically, the invention concerns designing analytical, diagnostic and therapeutic protocols and agents for such disease states and conditions through recognition of the central role of SAM and its metabolic pathways in controlling cell metabolism, cell growth and intercellular communication.
2. Description of the Background Art
It is commonly believed that an understanding of cellular metabolism and function, as well as the nature of biological degeneration and the creation of disease conditions, can be achieved by ascertaining the genetic information contained in eukaryotic cells and understanding how this genetic information is transcribed and translated into proteins which then control chemical conversions within the cell. The present conceptual frame work considers DNA as the core of life. Within this framework, the function of proteins is commonly assumed to be regulated in large part by phosphorylation and dephosphorylation of relevant proteins at appropriate times.
The present invention was made in response to the absence of a greater unifying relationship between small molecule biochemistry and the macromolecules RNA, DNA and protein. Present-day molecular biology is focused completely on macromolecules and has provided essentially no connection with the small molecules which carry out the chemical reactions of life. In fact, the study of small molecules in the biological and biochemical sciences has not been in vogue for the last 20 years, as can be evidenced by examining any issue of the journals Science, Nature or Cell.
The present inventors have recognized that the focus of the present paradigm for metabolic management are incorrect or, at best very incomplete. Such a recognition demands a "paradigm shift" of the sort described by Thomas Kuhn in The Structure of Scientific Revolutions (2nd ed., University of Chicago Press (1970)). The prevailing view will change completely when a single paradigm shift is made which defines the conceptual basis for the present invention This paradigm shift is to the view of the present invention, that life is regulated by S-adenosyl-L-methionine (SAM) through at least eight "donor/cleavage" pathways. In addition, as conceived by the present inventors, significant regulation occurs at the RNA level as opposed to the DNA level. Hence, there never was a transition from the "RNA world" to the "DNA world" as is the prevailing view in the scientific community.
It is proposed here that our present state of knowledge and interpretation of disease has evolved into two classes which are termed by the present inventors: (1) "exogenous disease", for example that caused by viruses, bacteria and organisms exogenous to the affected subject, and (2) "endogenous disease", such as cancer and arthritis, largely associated with internal changes in the affected subject and frequently associated with aging. At present, understanding of exogenous disease is greater due to our knowledge of the external and identifiable causative agents. This knowledge has provided diagnostic and therapeutic procedures which are quite effective against many pathological states, such as bacterial infections. Comparatively speaking, we understand surprisingly little about endogenous diseases. While an enormous body of facts surrounding most endogenous diseases exists, we unfortunately have minimal molecular understanding of their etiology. The reason for this is simple: we have been adhering to the wrong paradigm, a DNA-centered conceptual framework which does not include regulation through RNA or through the eight pathways of SAM.
With the new view of life in accordance with the paradigm shift described herein, the diseases of man take on a striking simplicity. Most importantly, and practically, from this novel view of life and biochemical processes, the present invention suggests ways to discover and implement new diagnostics and therapeutics for virtually every endogenous disease of man, as well as many exogenous diseases such as bacterial and viral infections.
The recognition of the centrality of the eight "donor/cleavage" pathways of SAM by the present inventors and their application to disease will radically alter the existing paradigm since SAM merges the biochemistry of small molecules with that of macromolecules. In order to design methods to assess the overall metabolic state of a eukaryotic organism and to modulate this state in response to a disease or a dysfunctional condition, the central role of SAM in controlling a host of biochemical reactions must be recognized and employed.
A number of publications which describe SAM and SAM metabolism are delineated below.
Several U.S. patents describe SAM, its activity, and various metabolites and utilities thereof. U.S. Pat. No. 4,369,177 discloses a stable composition of SAM which includes a salt of SAM in a pharmaceutically acceptable water-soluble salt of a bivalent or trivalent metal. SAM is said to have pharmaceutical effects in various disorders including adipohepatica, hyperlipemia, arteriosclerosis, depression, arthritis deformans, pains in some neurological manifestations and sleeplessness.
U.S. Pat. No. 4,956,173 discloses use of ademethionine (a common name for a SAM salt) for the preparation of pharmaceutical or cosmetic compositions for counteracting aging of the skin. Ademethionine is said to be a physiological molecule of virtually ubiquitous distribution in the tissues and liquids of the organism where it is involved in important biological processes as a donor of methyl groups in numerous transmethylation reactions and as a precursor of physiological sulfur compounds such as glutathione, cysteine, taurine and CoA. Levels of SAM are known to be high in children and adolescents whereas they are lower in adults and subsequently decrease in presenility and senility. SAM is the active principle of drugs used especially for the treatment of degenerative osteoarthropathy where it has an important role through its antiphlogistic and analgesic activity due to its intervention in the metabolism of arachidonic acid and prostaglandins. Ademethionine is also indicated in the treatment of depressive syndromes.
U.S. Pat. No. 4,764,603 discloses SAM salts with water-soluble polyanions such as polyphosphates, polyvinylsulfonates, sulfates or phosphates, polyacrylates, polystyrene sulfonates.
U.S. Pat. No. 5,073,546 discloses liposoluble salts of SAM with acyl derivatives of taurine. This reference lists a number of important biochemical functions of SAM and summarizes various pharmacologic effects of SAM in test models and the use in clinical pathologies.
U.S. Pat. No. 4,605,625 discloses production of S-adenosyl-L-homocysteine (SAH) by contacting adenosine with D-homocysteine in an aqueous medium in the presence of Pseudomonas cells having the ability to racemize D-homocysteine to D-L-homocysteine and in the presence of SAH hydrolase to synthesize SAH. SAH is said to be an important biologically active substance formed by a methyl group donating reaction in vivo involving SAM. SAH was said to be efficacious as a sedative and a sleep-inducing agent
U.S. Pat. No. 4,562,149 discloses yeast cultures containing SAM in high concentrations and a process for producing SAM by cultivating the yeast in a liquid culture medium containing methionine.
U.S. Pat. No. 4,242,505 discloses stabilized SAM compositions a sulfuric acid equivalent and a nucleoside sulfate. U.S. Pat. No. 4,057,686 discloses stable sulfonic acid salt of SAM. U.S. Pat. No. 4,028,183 discloses preparation of double salts of SAM by the action of the enzyme ATP-methionine-adenosyl-transferase on a mixture of ATP and methionine. U.S. Pat. No. 3,954,726 discloses double salts of SAM with sulfuric acid and p-toluene sulfonic acid.
U.S. Pat. No. 3,962,034 discloses production of SAM and methylthioadenosine by yeast cultured in media containing L-methionine.
U.S. Pat. No. 4,599,309 discloses treatment of yeast cells following cultivation to facilitate product recovery Among the many substances recoverable from such cells are SAM.
U.S. Pat. No. 5,100,786 discloses a gene which provides cellular resistance to at least one methionine derivative and is capable of enhancing accumulation of SAM in a cell. Also disclosed are a plasmid containing this gene, a cell transformed with the plasmid and a process for producing SAM using the above cells in a large amount at low cost. SAM is said to participate in metabolism of fats, proteins, sugar chains and the like and to have effects in the therapy of excessive lipemia, arteriosclerosis, psychosis manifestations such as depression and neuropathic diseases, degenerative arthropathy, neuropathic pain, sleeplessness, brain damage, and the like. The gene described in this reference is referred to as the "SAM gene" which enables cells to accumulate SAM in large amounts though the gene also provides the cell with ethionine resistance.
U.S. Pat. No. 5,132,291 discloses antiviral purine nucleosides, analogs and prodrugs and methods of enhancing the antiviral activity of AZT. Some of the purine nucleoside analogs inhibit SAH hydrolase, an enzyme which converts SAH to adenosine and homocysteine. Inhibition of this enzyme causes a build-up of SAH, which in turn inhibits SAM-mediated methylation and the conversion of SAM to SAH. This latter inhibition is said to destabilize viral mRNA which is normally stabilized in part by methylation at the 5'-terninus to form the cap structure found in mammalian mRNA.
U.S. Pat. No. 4,376,116 discloses compounds which inhibit polyamine biosynthesis and cites U.S. Pat. Nos. 3,954,726 and 4,028,183 as describing the preparation of stable salts of SAM which is the parent compound of decarboxylated SAM (dcSAM). Such polyamine synthesis inhibitors are said to be useful as antiparasitic agents and in the treatment of cancer and cystic fibrosis.
U.S. Pat. No. 5,087,417 states that the biosynthetic path leading to ethylene formation begins with conversion of methionine to SAM, SAM to 1-amino-cyclopropane-1-carboxylic acid (ACC), and thence to ethylene. This reference describes the isolation and identification of the compounds which inhibit senescence in perishable plant tissue from petals of senescing carnation flowers. The active compound, a glucose ester of ferulic acid, inhibits ACC-to-ethylene conversion, ethylene formation in vitro and lipoxygenase activity.
U.S. Pat. No. 4,275,150 discloses an assay for measurement of normetanephrine in biological systems of patients in particular for hypertension or for detection of pheochromocytoma. This method utilizes conversion of normetanephrine to its N-methylated (and tritiated) derivative, metanephrine, utilizing SAM as methyl donor
U.S. Pat. Nos. 5,264,355, 5,198,358, 5,149,701 discloses a new methylating enzyme from Streptomyces, which uses SAM as a methyl donor in methylating various FK 506-related agents. These immunosuppressants are said to be useful for treating autoimmune diseases, infectious diseases, graft rejection, reversible obstructive airway disease, inflammatory and hyperproliferative skin disease, cutaneous manifestations of immunologically mediated illness, male pattern alopecia and alopecia senilis.
None of the documents cited above provide any insight into the present invention nor do they lead a person of ordinary skill in the art to the present claims.